{"@context":"https://schema.org","@type":"Dataset","@id":"https://zipradar.org/topic/flood-zone/03801/","name":"Flood zone for ZIP 03801 — Portsmouth (NH), NH","description":"Flood zone data for ZIP 03801 (Portsmouth (NH), New Hampshire), sourced from FEMA NFHL.","topic":{"slug":"flood-zone","label":"Flood zone","source":"FEMA NFHL","sourceUrl":"https://www.fema.gov/flood-maps/national-flood-hazard-layer","refreshCadence":"Quarterly LOMA updates","summary":"Pages show the flood zone code, what it means in plain English (1% annual chance zone, 0.2% annual chance zone, or outside mapped hazard), and the base flood elevation where assigned.","limitations":"For an official flood-zone determination (required by lenders), consult the FEMA Map Service Center directly. zipradar shows informational classifications only."},"place":{"zip":"03801","city":"Portsmouth (NH)","state":"NH","stateFull":"New Hampshire","county":"Rockingham County (NH)","countySlug":"rockingham-county","geo":{"latitude":43.0772,"longitude":-70.7626}},"stateContext":{"topConcern":"Radon, lead in older housing","narrative":"New Hampshire is uniformly Zone 1 radon. Older Manchester + Nashua + Portsmouth housing stock carries lead-service-line risk. Coastal flood zones limited to small NH coastline."},"radonZone":null,"airQuality":null,"datePublished":"2026-04-24","dateModified":"2026-09-07","canonicalUrl":"https://zipradar.org/topic/flood-zone/03801/","zipDashboardUrl":"https://zipradar.org/zip/03801/","zipDashboardApiUrl":"https://zipradar.org/api/zip/03801/","primarySourceUrl":"https://www.fema.gov/flood-maps/national-flood-hazard-layer","license":{"content":"CC-BY-4.0","attribution":"zipradar.org — https://zipradar.org/topic/flood-zone/03801/"}}